A newly investigated 290 million year old fossil may be an evolutionary missing link in the amphibian family tree. The fossil was collected in Texas by a palaeontologist with the Smithsonian Institution in the mid-1990s. The fossil eventually ended up at the National Museum of Natural History in Washington, D.C., where it was re-discovered and investigated in 2004.

The new analysis of the fossil has been carried out by Jason Anderson, a comparative biologist at the University of Calgary, Canada. According to Anderson, the fossil has an overall amphibian look but with interesting archaic features. The animal resembles a salamander, but the tail is stubby and the ears are similar to the ears of a frog.

“So it’s kind of a frogamander, if you will,” Anderson sais to National Geographic News.

The fossilized species has been given the name Gerobatrachus hottoni. Until recently, scientists believed that frogs, salamanders and the wormlike caecilians all hailed from a common ancestor. Gerobatrachus hottoni suggests that frogs and salamanders are much more closely related to each other than to the caecilians.

Read more in Anne Casselman’s article for National Geographic News.

http://news.nationalgeographic.com/news/2008/05/080521-frog-fossil.html

The study of the fossil appears in this week’s (May 21^st 2008) issue of the journal Nature.

Giant Mekong catfish. Copyright www.jjphoto.dk

According to Zeb Hogan, head of the National Geographic Society’s Megafishes Project, a new dam project planned for Khone Falls in Laos threatens the migration of the Mekong giant catfish. The largest Mekong giant catfish ever caught weighed in at an astonishing 293 kilograms (646 pounds), but the existence of this magnificent species is unfortunately threatened in the wild and it is currently listed as critically endangered by the World Conservation Union.

You can find out more by visiting National Geographic at http://news.nationalgeographic.com/news/2008/04/photogalleries/catfish-pictures/

The Mekong giant catfish inhabits the Mekong River Delta in South-East Asian and can be found not only in Laos, but also in nearby Cambodia. Earlier, the species lived in Thailand as well but it is now believed to have become completely eradicated from the Thai part of the Mekong River Delta. (It has however been introduced as a sport fish in a number of lakes in Thailand, so the species has not vanished completely from Thai waters.) The situation is critical for the populations in Laos and Cambodia as well and the new dam might worsen an already precarious situation. The primary threats against the Mekong giant catfish are habitat destruction, pollution and over fishing. You can find more information about the Mekong giant catfish here: http://www.aquaticcommunity.com/catfish/giantmekong.php